Field
Implementations of the present disclosure generally relate to semiconductor processing and more specifically to an apparatus for deploying and monitoring a process using a sensing device in a semiconductor processing system.
Description of the Related Art
FIG. 1 (Prior Art) is a schematic cross sectional side view of a plasma process apparatus 100 used in FIG. 5 to describe various implementations. The plasma process apparatus in FIG. 1 is an inductively coupled plasma chamber and may be utilized alone or, as a processing module of an integrated semiconductor substrate processing system, or cluster tool, such as CENTURA® integrated semiconductor substrate processing system, available from Applied Materials, Inc. of Santa Clara, Calif.
As shown in FIG. 1 (Prior Art), the plasma process apparatus 100 may be a plasma process chamber 110 including a chamber body 130 and a chamber lid 120 that together define a processing volume 112. The plasma process chamber 110 may further include a substrate support 116 disposed in the processing volume 112, a plasma source assembly 160 disposed over the chamber lid 120, and a controller 140. The chamber body 130 may be coupled to an electrical ground 134. In some implementations, the substrate support 116 may be coupled, through a matching network 124, to a biasing power source 122.
The plasma source assembly 160 may include at least two RF coils, such as a first coil 109 and a second coil 111 surrounding the first coil 109. The first coil 109 and the second coil 111 may be concentric. An annular space 115 is defined between the first coil 109 and the second coil 111. The first coil 109 may be supported by two or more supports 162 and the second coil 111 may be supported by two or more supports 164. Supports 162, 164 may be made of a dielectric material and may be disposed on the chamber lid 120. Each coil 109, 111 may be coupled, through a matching network 119, to an RF power source 118.
The RF power source 118 may be capable of producing up to 13 W/cm2 at a tunable frequency in a range from about 50 kHz to about 13.56 MHz. In some implementations, a power divider 104, such as a dividing capacitor, may be provided to control the relative quantity of RF power provided by the RF power source 118. The power divider 104 may be disposed in the line coupling the first coil 109 and the second coil 111 to the RF power source 118 for controlling the amount of RF power provided to each coil. In other implementations, each coil may be separately powered by a different RF source.
During operation, a substrate 114 may be placed on the substrate support 116 and process gases may be supplied from a gas panel 138 through entry ports 126 to form a gas mixture 150 within the processing volume 112. The gas mixture 150 may be transformed into a plasma 155 in the processing volume 112 by coupling RF power to the gas mixture from the first and second coils 109, 111 that are energized by the RF power source 118. The pressure within the processing volume 112 may be controlled using a throttle valve 127 and a vacuum pump 136. The temperature of the chamber body 130 may be controlled using liquid-containing conduits (not shown) that run through the chamber body 130. In one embodiment, helium gas from a gas source 148 may be provided via a gas conduit 149 to channels defined between the backside of the substrate 114 and grooves (not shown) disposed in the surface of the substrate support 116. The helium gas may be used to facilitate heat transfer between the substrate support 116 and the substrate 114.
The controller 140 may include a central processing unit (CPU) 144, a memory 142, and support circuits 146 for CPU 144 and may facilitate control of the components of the plasma process chamber 110 and, as such, of methods discussed herein. The controller 140 may be one of any form of general-purpose computer processor that can be used in an industrial setting for controlling various chambers and sub-processors. The memory 142, such as computer readable-medium, of the controller 140 may be one or more of readily available memory, such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, or any other form of digital storage, local or remote. The support circuits 146 are coupled to the CPU 144 for supporting the CPU 144 in any conventional manner. The circuits 146 may include cache, power supplies, clock circuits, input/output circuitry and sub-systems. The methods described herein may be stored in the memory 142 as software routine that may be executed or invoked to control the operation of the plasma process chamber 110 in the manner described herein.
The fabrication of integrated circuits in the semiconductor industry typically employs plasma to create and assist surface chemistry within a plasma reactor necessary to remove material from and deposit material to a substrate. In general, plasma is formed within the plasma reactor under vacuum conditions by heating electrons to energies sufficient to sustain ionizing collisions with a supplied process gas. Moreover, the heated electrons can have energy sufficient to sustain dissociative collisions and, therefore, a specific set of gases under predetermined conditions (e.g., chamber pressure, gas flow rate, etc.) are chosen to produce a population of charged species and chemically reactive species suitable to the particular process being performed within the chamber (e.g., etching processes where materials are removed from the substrate or deposition processes where materials are added to the substrate).
During, for example, an etch process, monitoring the plasma processing system can be essential when determining the state of a plasma processing system and determining the quality of devices being produced. Surface acoustic wave (SAW) based devices and sensors are advantageous for use in semiconductor processing equipment in that they are wireless and passive, requiring no battery, and may be placed in remote or hard to reach areas in the processing environment. However, SAW sensors are unable to withstand the harsh processing environments, which may include corrosive plasmas and RF energy inside the semiconducting processing chamber. Additionally, traditional SAW sensors include layers of lithium, niobium, or other elements not permitted in semiconductor processing equipment. Therefore, what is needed in the art is an apparatus for effectively packaging a SAW sensor for operation in a semiconductor processing chamber.